Rotary-style peristaltic pumps often generally include a cassette mounted to and supported by a pump body. In some instances, the pump body includes a cavity formed therein and configured to receive a planetary assembly of rollers. The rollers revolve together when rotationally driven by a drive shaft when the drive shaft is powered by a pump motor.
The cassette generally includes a body having a flexible tube disposed therethrough. When the cassette is mounted to the pump body, the flexible tube surrounds a portion of the assembly of rollers. In response to rotational movement of the rollers, portions of the flexible tube in contact with the rollers compress or otherwise occlude against a wall of the cassette. As a result, fluid traveling through the tube is temporarily trapped in the tube between the occluded points. The trapped fluid is released from the tube when the occlusion force on the tube is released. In this manner, fluid is urged through the tube via peristaltic wave action.
Peristaltic infusion pumps are often used to deliver fluid in a controlled manner, such as, for example, the intravenous delivery of pharmaceutical compositions to a patient. These peristaltic pumps typically use disposable cassettes, where the pump assembly is designed to accommodate the loading of the cassette, as well as the removal of the cassette from the assembly. Such designs, however, may undesirably involve relatively difficult cassette loading and removal schemes.
U.S. Pat. No. 7,934,912 discloses a peristaltic pump assembly wherein a removable cassette is installed in the pump body by sliding the cassette onto a cylindrical mounting pin extending from the pump body. The cassette includes a hinge journal sized to receive the mounting pin, and the cassette is slid onto the mounting pin in an axial direction of the mounting pin. Once installed in this manner, the cassette is rotatable about the mounting pin until a retaining feature on the cassette spaced from the hinge journal engages a corresponding retaining feature on the pump body. Thus, if the axis of the mounting pin is considered the Z axis, the cassette must be moved along the Z axis toward the pump body to slide the cassette on the mounting pin, and then the cassette may be rotated about the Z-axis in an X-Y plane. Similar but reverse steps are necessary to remove the cassette from the pump body. While this “side loading” arrangement provides for easy installation and removal of the cassette, the cassette mounting pin must be exposed or accessible to receive the cassette and allow removal of the cassette. A portion of the cassette that includes the hinge journal must also remain exposed or accessible for the same reasons. Therefore, improved protection against inadvertent movement of the cassette is desired.